The side-coupling arrangement used in conventional accelerator cavities results in a large and complex assembly. Injectors using cavities of this type combined with thermionic cathodes typically exhibit an electron capture efficiency of less than 40%.
In order to reduce the performance limitations of side-coupled cavities, resonant coupling slots have been proposed in multi-cell accelerator structures. However, resonant slots require long slot openings and lead to high power losses and reduced efficiency.
This is important for industrial or medical applications requiring high average power beams. Unlike pulsed accelerators, where the thermal issues are less important, this invention is aimed at CW and high duty factor applications with high average beam power. The inclusion of the internal cooling is important in this regard and yields an additional advantage
Accordingly, it would be desirable to provide a more compact and simpler accelerator arrangement and method for increasing the electron capture efficiency. Improving the power efficiency of the accelerating structure and the electron capture efficiency leads to a more compact and cost effective device and reduces the amount of input power required to drive the accelerator. This is particularly important for Continuous wave (CW) and high duty factor accelerators where the input power and cooling requirements are significant.